Transcript Slide 1

IMPLICATIONS OF GLOBAL
ENVIRONMENTAL CHANGE FOR
FLOOD-PRONE AREAS IN THE
EASTERN HIMALAYAN REGION
Ahsan Uddin Ahmed
Bangladesh Unnayan Parishad (BUP)
GECAFS-IGP-APN Project Launching Meeting, Kathmandu, 29-30 June 2006
Implications of GEC for Flood-prone Areas in the Eastern Himalayan Region GECAFS-IGP-APN Project Launching Meeting
The Eastern Himalayan [i.e., Ganges-Brahmaputra-Meghna (GBM)]
River Systems in South Asia
Implications of GEC for Flood-prone Areas in the Eastern Himalayan Region GECAFS-IGP-APN Project Launching Meeting
GBM River Systems
Spreading over five countries: Bhutan, China, India, Nepal, and
Bangladesh
The three basins cover an area of 1.75 Million square kilometers
The second largest outfall after the Amazon System
Perennial Rivers
Average annual flow: 1360 Billion cubic meters
Contributed to the development of the largest delta on earth
These river systems support agriculture-based livelihoods of about
650 Million people in South Asia
Implications of GEC for Flood-prone Areas in the Eastern Himalayan Region GECAFS-IGP-APN Project Launching Meeting
GBM Rivers are strongly
influenced by SW-Monsoon
Monsoon generates ‘too much
water’
There is water scarcity during
the dry winter season (‘too little
water’)
High spatial and temporal
variability in water availability
throughout the GBM region
cause problems
Floods
Ag. Droughts
Salinity Ingress along the coast
THE HK HIMALAYAS
Implications of GEC for Flood-prone Areas in the Eastern Himalayan Region GECAFS-IGP-APN Project Launching Meeting
Over 80% of rainfall occurs during June
– September
The River Systems cannot drain
Riverbank overtopping and flood
Catastrophic floods
In India (Bihar, West Bengal, Assam)
In Nepal (Terai region)
In Bangladesh
Implications of GEC for Flood-prone Areas in the Eastern Himalayan Region GECAFS-IGP-APN Project Launching Meeting
Concerns of GEC
Global Climate
Change
Too much water in
monsoon
monsoon
>>
Acid Rain
Sea level rise
Asian Brown Cloud
Urbanization
Globalization
Other local factors
Population dynamics
>>
>>
River water
levels
>>
Unprotected area:
bank overflow
>>
Sedimentation
in floodplains
>>
Climate
change
>>
Backwater
effect
>>
Water logging
>>
>>
>>
Precipitation
Dynamics in geophysical systems
Social and economic
aspects
Protected area:
risk of
flooding
Bed levels
Ahmed et al., 1998
>>
Runoff
>>
Maximum
river flow
>>
Impacts on flood
>> : Increase expected
<< : Reduction expected
Implications of GEC for Flood-prone Areas in the Eastern Himalayan Region GECAFS-IGP-APN Project Launching Meeting
Extent of Change:
There will be a
general rise in
surface average
temperature:
1.3°C by 2030s;
2.6°C by 2070s.
Monsoon rainfall
will increase by
7% by 2050s and
11% by 2080s.
Number of rainy
days in the region
will increase by
about 20 days.
More catastrophic
floods
Courtesy: IITM
Implications of GEC for Flood-prone Areas in the Eastern Himalayan Region GECAFS-IGP-APN Project Launching Meeting
10
Observed
CTL
GHG (2041-60)
9
8
Rainfall (mm/day)
7
6
5
4
3
2
1
0
Jan
Feb
Mar
Apr
May
Jun
Jul
Months
Aug
Sep
Oct
Nov
Dec
Courtesy: IITM
Models such as HadCM project wetter monsoon over the South Asian Region. Wetter
monsoon means higher amounts of water being available.
Implications of GEC for Flood-prone Areas in the Eastern Himalayan Region GECAFS-IGP-APN Project Launching Meeting
Global Warming will also cause rise in sea level. Along the coastal
rivers, where discharge requirement is even higher than the
floodplains in general, a combination of se level rise and sea level
will increase flood vulnerability.
Too much water in
monsoon
monsoon
Protected area:
risk of
flooding
Bed levels
>>
Sea level rise
>>
>>
River water
levels
>>
Unprotected area:
bank overflow
>>
Sedimentation
in floodplains
>>
Climate
change
>>
Backwater
effect
>>
Water logging
>>
>>
>>
Precipitation
>>
Runoff
>>
Maximum
river flow
>>
Impacts on flood
>> : Increase expected
<< : Reduction expected
Ahmed et al., 1998
Implications of GEC for Flood-prone Areas in the Eastern Himalayan Region GECAFS-IGP-APN Project Launching Meeting
Since mid-1970s, Bangladesh has enhanced its capacity to deal with
moderate (once in a twenty-year flood) floods. Such a coping was made
possible by building embankments. However, flood controlling structures
are not so effective to offer protection against catastrophic floods.
Choudhury et al., 2003
Implications of GEC for Flood-prone Areas in the Eastern Himalayan Region GECAFS-IGP-APN Project Launching Meeting
Implications for urban areas
Trapped in floodwaters
?
Level of inundation in Dhaka city
Implications of GEC for Flood-prone Areas in the Eastern Himalayan Region GECAFS-IGP-APN Project Launching Meeting
IMPLICATIONS OF FLOODS: HUMAN
DIMENSIONS
Immediate Effects
• Temporary Displacement
• Drowning and Snake-bites
Problems Faced
by Women and
Children
• Loss of Income & Economic Opportunities
Lack of Supply of
• Non-availability of Potable Water
Commodities
• Suffering from Water-borne Diseases
• Lack of Cooking Energy
• Inability to Purchase Consumable Items
Price hike
Implications of GEC for Flood-prone Areas in the Eastern Himalayan Region GECAFS-IGP-APN Project Launching Meeting
Implications of GEC for Flood-prone Areas in the Eastern Himalayan Region GECAFS-IGP-APN Project Launching Meeting
IMPLICATIONS OF FLOODS: HUMAN
DIMENSIONS
Long Term Effects
• Crop Failure and Food Security
• Energy Security
• Rehabilitation
• Disruption of Services
Education
Transportation
Health Care
Environmental Services
Security
Problems Faced
by Women and
Children
Lack of Supply of
Commodities
Price hike
Implications of GEC for Flood-prone Areas in the Eastern Himalayan Region GECAFS-IGP-APN Project Launching Meeting
Implications of GEC for Flood-prone Areas in the Eastern Himalayan Region GECAFS-IGP-APN Project Launching Meeting
Implications of GEC for Flood-prone Areas in the Eastern Himalayan Region GECAFS-IGP-APN Project Launching Meeting
THANK YOU
Implications of GEC for Flood-prone Areas in the Eastern Himalayan Region GECAFS-IGP-APN Project Launching Meeting
In the dry season, reduced river flows
give rise to salinity ingress along the
coastal rivers
Currently, over 15 million people in
Bangladesh alone are forced to drink
saline water